Embodiments described herein relate generally to improved systems and methods for the desalination of seawater and, more particularly, to methods and apparatus for the treatment and disposal of wastewater having a relatively low salt concentration and concentrate (brine) generated from desalination plants having a relatively high salt concentration.
The desire to make drinkable, potable water out of seawater has existed for a long time. Several approaches can be taken to remove the salt and other chemicals. One approach to desalination is reverse osmosis. This method uses pressure to force salty feed water against membranes which allows the relatively salt free water to pass through, but not much of the salts or other minerals, to create a concentrate (brine) and a permeate. Desalination systems are disclosed in U.S. Pat. No. 6,946,081, and U.S. application Ser. No. 12/424,125, the disclosures of which are incorporated by reference herein in their entirety. The permeate from the desalination plant may be used as potable water for home use, agriculture, or industry. The concentrate must be properly disposed of, often by discharge to a body of water, such as an ocean, sea, or other body of salty water. However, the discharge of concentrated seawater from a desalination facility into a natural environment of water having a lower concentration of salts and minerals may harm organisms or otherwise damage the natural environment.
Similarly, wastewater having a relatively low salt concentration from other water treatment processes are also disposed of by discharge into bodies of salty water. The discharge of fresh water or water having a relatively low salt concentration into a natural environment of water having a higher concentration of salts and minerals may harm organisms or otherwise damage the natural environment. For example, the city of San Jose, Calif. limits the flow of treated municipal and industrial wastewater, into the south end of San Francisco Bay because too much of such low salt concentration wastewater could convert the salt marsh located there into a brackish marsh, endangering the resident animal and plant life.
Thus, there is a need for methods and apparatus to properly dispose of concentrate from a water desalination plant and treated wastewater from a waste treatment plant into surface bodies of water or otherwise without causing environmental damage.